Mobile services providers may operate multiple heterogeneous access technologies and networks. Worldwide Interoperability for Microwave Access (WiMAX) is a wireless communication access technology intended to be deployed in accordance with the Institute of Electrical and Electronics Engineers (IEEE) standard referred to as IEEE 802.16. WiMAX networks provide broadband wireless communication over distances which are relatively long. Initial WiMAX deployment may cover only limited areas of service that may already be serviced by the third generation (3G) type cellular networks, such as promulgated by the 3rd Generation Partnership Project (3GPP). Thus, at least during initial deployment of WiMAX networks, islands of WiMAX coverage areas may exist within cellular 3G coverage areas. Hence, it may be useful for a 3G network service provider that deploys WiMAX services to converge WiMAX access and 3G access with seamless vertical mobility, or interaccess. Furthermore, dual mode devices that are capable of communicating with both 3G networks and WiMAX networks are expected to be deployed.
Current solutions for network interaccess in 3GPP standards and the cellular industry utilize Layer 3 (L3) protocols (i.e., client-based Mobile IP) for providing mobility between access technologies. However, such L3 protocol-based methods require simultaneous radio operation of both access technologies to execute a handover operation between a non-WiMAX network and a WiMAX network. Further, client-based Mobile IP techniques may experience significant latency in performing interaccess handovers that could hinder operation of real-time services such as Voice over Internet Protocol (VoIP) applications or the like.
Protocols have been developed in WiMAX to provide for single-radio handover between a WiMAX network and a non-WiMAX network. In single-radio handovers various network elements cooperate to manage the handover process between heterogeneous access networks.